At the bottom of an icy Antarctic lake, a thin, slimy layer of bright green microbes is generating a tiny oasis of oxygen that might give a picture of what early Earth looked like before oxygen became common in the atmosphere.

Using a specially designed hot-water drill to cleanly bore through a half mile of ice, a National Science Foundation (NSF)-funded team of researchers has become the first ever to reach and sample the "grounding zone," where Antarctic ice, land and sea all converge.

Researchers this week published a paper confirming that the waters and sediments of a lake that lies 800 meters (2,600 feet) beneath the surface of the West Antarctic ice sheet support "viable microbial ecosystems."